Little is known on the end-of-life (EOL) care of terminal breast cancer in women with severe psychiatric disorder (SPD). The objective was to determine if women with SPD and terminal breast cancer received the same palliative and high-intensity care during their end-of-life than women without SPD. Study design, setting, participants. This population-based cohort study included all women aged 15 and older who died from breast cancer in hospitals in France (2014-2018). Key measurements/outcomes. Indicators of palliative care and high-intensity EOL care. Multivariable models were performed, adjusted for age at death, year of death, social deprivation, duration between cancer diagnosis and death, metastases, comorbidity, smoking addiction and hospital category. The analysis included 1742 women with SPD (287 with bipolar disorder, 1075 with major depression and 380 with schizophrenia) and 36,870 women without SPD. In multivariate analyses, women with SPD had more palliative care (adjusted odd ratio aOR 1.320, 95%CI [1.153-1.511], p < 0.001), longer palliative care follow-up before death (adjusted beta = 1.456, 95%CI (1.357-1.555), p < 0.001), less chemotherapy, surgery, imaging/endoscopy, and admission in emergency department and intensive care unit. Among women with SPD, women with bipolar disorders and schizophrenia died 5 years younger than those with recurrent major depression. The survival time was also shortened in women with schizophrenia. Despite more palliative care and less high-intensity care in women with SPD, our findings also suggest the existence of health disparities in women with bipolar disorders and schizophrenia compared to women with recurrent major depression and without SPD. Targeted interventions may be needed for women with bipolar disorders and schizophrenia to prevent these health disparities.